This is a collection of Intel®’ IA32® Software Developer's Manuals (URL of the day) and AMD' AMD64 Architecture Programmer's Manual together with the related specifications, application notes, white papers, and change logs. The collection aims to keep all available revisions. It was originally created by Michal Necasek, see OS/2 Museum.

If you have a public document, related to the IA32® specifications and missing from the collection, please mail it to me. The content of this URL and all sub-ULRs is available for convenient bulk download by rsync x86docs password "" (empty).

DBGPRCR

DBGPRCR, Debug Power Control Register

The DBGPRCR characteristics are:

Purpose

Controls behavior of the PE on powerdown request.

Configuration

AArch32 System register DBGPRCR bits [31:0] are architecturally mapped to AArch64 System register DBGPRCR_EL1[31:0].

AArch32 System register DBGPRCR bit [0] is architecturally mapped to External register EDPRCR[0].

This register is present only when FEAT_AA32EL1 is implemented. Otherwise, direct accesses to DBGPRCR are UNDEFINED.

Attributes

DBGPRCR is a 32-bit register.

Field descriptions

313029282726252423222120191817161514131211109876543210
RES0CORENPDRQ

Bits [31:1]

Reserved, RES0.

CORENPDRQ, bit [0]
When FEAT_DoPD is implemented:

Core no powerdown request. Requests emulation of powerdown.

This request is typically passed to an external power controller. This means that whether a request causes power up is dependent on the IMPLEMENTATION DEFINED nature of the system. The power controller must not allow the Core power domain to switch off while this bit is 1.

CORENPDRQMeaning
0b0

If the system responds to a powerdown request, it powers down Core power domain.

0b1

If the system responds to a powerdown request, it does not powerdown the Core power domain, but instead emulates a powerdown of that domain.

In an implementation that includes the recommended external debug interface, this bit drives the DBGNOPWRDWN signal.

It is IMPLEMENTATION DEFINED whether this bit is reset to the Cold reset value on exit from an IMPLEMENTATION DEFINED software-visible retention state. For more information about retention states see 'Core power domain power states'.

Note

Writes to this bit are not prohibited by the IMPLEMENTATION DEFINED authentication interface. This means that a debugger can request emulation of powerdown regardless of whether invasive debug is permitted.

On a Cold reset, if the powerup request is implemented and the powerup request has been asserted, this field is set to an IMPLEMENTATION DEFINED choice of 0 or 1. If the powerup request is not asserted, this field is set to 0.


Otherwise:

Core no powerdown request. Requests emulation of powerdown.

This request is typically passed to an external power controller. This means that whether a request causes power up is dependent on the IMPLEMENTATION DEFINED nature of the system. The power controller must not allow the Core power domain to switch off while this bit is 1.

CORENPDRQMeaning
0b0

If the system responds to a powerdown request, it powers down Core power domain.

0b1

If the system responds to a powerdown request, it does not powerdown the Core power domain, but instead emulates a powerdown of that domain.

In an implementation that includes the recommended external debug interface, this bit drives the DBGNOPWRDWN signal.

It is IMPLEMENTATION DEFINED whether this bit is reset to the value of EDPRCR.COREPURQ on exit from an IMPLEMENTATION DEFINED software-visible retention state. For more information about retention states see 'Core power domain power states'.

Note

Writes to this bit are not prohibited by the IMPLEMENTATION DEFINED authentication interface. This means that a debugger can request emulation of powerdown regardless of whether invasive debug is permitted.

The reset behavior of this field is:

Accessing DBGPRCR

Accesses to this register use the following encodings in the System register encoding space:

MRC{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11100b0000b00010b01000b100

if !IsFeatureImplemented(FEAT_AA32EL1) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && MDCR_EL2().[TDE,TDOSA] != '00' then AArch64_AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HDCR().[TDE,TDOSA] != '00' then AArch32_TakeHypTrapException(0x05); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x05); end; else R(t) = DBGPRCR(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then Undefined(); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x05); end; else R(t) = DBGPRCR(); end; elsif PSTATE.EL == EL3 then R(t) = DBGPRCR(); end;

MCR{<c>}{<q>} <coproc>, {#}<opc1>, <Rt>, <CRn>, <CRm>{, {#}<opc2>}

coprocopc1CRnCRmopc2
0b11100b0000b00010b01000b100

if !IsFeatureImplemented(FEAT_AA32EL1) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA64EL2) && !ELUsingAArch32(EL2) && MDCR_EL2().[TDE,TDOSA] != '00' then AArch64_AArch32SystemAccessTrap(EL2, 0x05); elsif EL2Enabled() && IsFeatureImplemented(FEAT_AA32EL2) && ELUsingAArch32(EL2) && HDCR().[TDE,TDOSA] != '00' then AArch32_TakeHypTrapException(0x05); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x05); end; else DBGPRCR() = R(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then Undefined(); elsif HaveEL(EL3) && IsFeatureImplemented(FEAT_AA64EL3) && !ELUsingAArch32(EL3) && MDCR_EL3().TDOSA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_AArch32SystemAccessTrap(EL3, 0x05); end; else DBGPRCR() = R(t); end; elsif PSTATE.EL == EL3 then DBGPRCR() = R(t); end;


2026-03-12 12:23:09, 2025-09_rel_asl1

Copyright © 2010-2025 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.